Plant Breeding and Genetics Commons^™

Breeding For Fhb Resistance And Post-Harvest Quality In Soft Red Winter Wheat, Margaret E. Gillum

Theses and Dissertations--Plant and Soil Sciences

Soft red winter wheat (Triticum aestivum L.) is both an economically and nutritionally important crop in the global food supply. Despite its global importance, wheat is continually threatened by fungal diseases. Fusarium head blight (FHB), caused by Fusarium graminearum, is a devastating fungal disease affecting wheat worldwide, resulting in low yields, reduced test weight and mycotoxin production. The mycotoxin deoxynivalenol (DON) is toxic to humans, results in feed rejection in livestock, and is heavily monitored in the food supply. Because of wheat’s importance in the food system, post-harvest quality (milling, baking, and flavor) has been a growing area of …

Identifying Physiological, Morphological, And Genetic Drivers Of Key Intermediary Phenotypic Traits Associated With Stalk Lodging Resistance Within Genetically Diverse Maize Germplasm And Sorghum, Norbert Bokros

Theses and Dissertations--Plant and Soil Sciences

Maize stalk lodging reduces grain yields due to the permanent breakage or deformation of stalk tissue before grain harvest. To reveal new insights into the complex problem of maize stalk lodging, this dissertation will examine three primary objectives. First, the direct, diurnal influence of turgor pressure will be shown to have only marginal effects on stalk bending strength, a key trait associated with stalk lodging resistance. Up to a dozen individual stalks, grown to physiological maturity within the same field, were tested using a DARLING testing device. In parallel, stalk turgor status as measured by leaf water potential and turgor …

Winter Rye (Secale Cereale L.) Management And Production Profitability In Kentucky, And Heritability Of Sensory Attributes, Elzbieta Szuleta

Theses and Dissertations--Plant and Soil Sciences

Winter rye (Secale cereale L.) is a small grain crop characterized by outstanding tolerance to drought, low temperatures, soil salinity and relatively low nutritional requirements. Rye is widely used as a cover crop, well known for its deep root system and outstanding nitrogen scavenging ability. This crop is widely used as a feed for livestock but also it is beneficial in human nutrition. Because of its versatile use, nutritional benefits and unique aroma and flavor, especially for bread and whiskey, there is an increasing interest in this crop in the United States. Unfortunately, rye grain production in the United …

Improving Baking Quality Of Soft Red Winter Wheat In Kentucky Through Breeding And Sulfur-Nitrogen Fertility Management, Maria Paula Castellari

Theses and Dissertations--Plant and Soil Sciences

Soft Red Winter (SRW) wheat is an important crop grown on about 400,000 acres in Kentucky as a pivotal cash crop in the 3-crops-in-2-years rotation of corn, wheat, and soybean. The humid environment of Kentucky generates a high yielding wheat crop, with low protein concentration and weak gluten strength. This wheat is mainly sold to millers and used by the industry for cakes, pastries, cookies, and crackers. Conversely, there is a rapidly growing interest in identifying other value-added markets for this wheat different to commodity commercialization, such as artisan-baked goods and craft-distilled beverages. Evaluating the quality characteristics of wheat grown …

An Evaluation Of Eragrostis Tef For Future Cultivar Development, Eric Wayne Luteyn

Theses and Dissertations--Plant and Soil Sciences

The many benefits of utilizing teff (Eragrostis tef) as small grain is well documented in journal publications. Over time the domestication of this species has become essential to the diets of the local population and the livestock living in the African highlands. Current research points to a high diversity of trait characteristics found in many teff populations and the potential utilization of these traits to increase desirable characteristics in both grain and forage varieties. With the overarching goal of adding to what is already known about teff, this study evaluates the different traits that are of interest to …

Optical Seed Sorter-Based Selection Lowers Deoxynivalenol Accumulation In Soft Red Winter Wheat, William Jesse Carmack

Theses and Dissertations--Plant and Soil Sciences

Fusarium head blight (FHB) of wheat (Triticum aestivum L.) results in discolored grain contaminated with deoxynivalenol (DON). DON accumulation, an indicator of FHB resistance, can be quantified and used as the basis for direct phenotypic selection, but testing is expensive. The primary objective of this study was to evaluate an optical seed sorter as an alternative to DON testing for FHB resistance breeding. Three hundred F4 derived soft red winter wheat (SRWW) breeding lines were grown in an inoculated FHB nursery over several years in Lexington, KY. Grain from each breeding line was sorted using an optical seed sorter calibrated …

Genomic Selection Strategies To Predict Grain Yield And Disease Resistance Traits In A Wheat Breeding Program, Virginia Laura Verges

Theses and Dissertations--Plant and Soil Sciences

Genomic selection (GS) is a form of marker-assisted selection (MAS) that simultaneously estimates all locus, haplotype or marker effects across the entire genome to calculate genomic estimated breeding values (GEBVs). Since its inception, it has had the attention of breeders keen on finding tools to accelerate genetic gain and reduce phenotyping costs in the breeding program. A first objective of this study was to evaluate strategies to design the training population (TP) and validating population (VP) to estimate GEBVs for grain yield and agronomic traits for wheat breeding lines. Our results demonstrate that, despite the small family size, an approach …

Arthropod Resistant Tomatoes: Screening Tools, Yield And Nutritional Quality Of Interspecific Hybrids, Mohammad Hasan Salman Ali Dawood

Theses and Dissertations--Plant and Soil Sciences

Tomato (Solanum lycopersicum) is one of the most economically important vegetable crops grown around globe but is a host for numerous pests and pathogens. In the future, tomato breeders will have to focus on increasing fruit quantity and on enhancing pest resistance. Many accessions of the wild relative of tomato, S. habrochaites display high levels of resistance towards arthropods such as spider mites. The presence of the sesquiterpene hydrocarbon, 7-epi-zingiberene, found in S. habrochaites type IV trichomes has been associated with arthropod resistance. However, the presence of other compounds in its trichome secretions may also be related …

The Balancing Act Of Cytokinin In Environmental Stress Tolerance, Sumudu Sandeepani Karunadasa

Theses and Dissertations--Plant and Soil Sciences

Cytokinin, long known as a phytohormone that regulates plant growth and development, has been recently recognized as an important regulator of stress responses. However, our current knowledge about the mechanisms by which cytokinin regulates stress responses is fragmentary, as many of the studies in this field yielded conflicting results. Most of the work described here has focused on analyses of the molecular mechanisms of cytokinin-dependent regulation of growth and development under stress conditions, with an emphasis on the role of cytokinin-dependent regulation of protein synthesis in development and stress tolerance.

One of the important contributions of this study is the …

Gamete Nuclear Migration In Animals And Plants, Umma Fatema, Mohammad F. Ali, Zheng Hu, Anthony J. Clark, Tomokazu Kawashima

Plant and Soil Sciences Faculty Publications

The migration of male and female gamete nuclei to each other in the fertilized egg is a prerequisite for the blending of genetic materials and the initiation of the next generation. Interestingly, many differences have been found in the mechanism of gamete nuclear movement among animals and plants. Female to male gamete nuclear movement in animals and brown algae relies on microtubules. By contrast, in flowering plants, the male gamete nucleus is carried to the female gamete nucleus by the filamentous actin cytoskeleton. As techniques have developed from light, electron, fluorescence, immunofluorescence, and confocal microscopy to live-cell time-lapse imaging using …

Breeding For Tomato Resistance To Spider Mite Tetranychus Urticae Koch (Acari: Tetranychidae), Ammar Sami Al-Bayati

Theses and Dissertations--Plant and Soil Sciences

Cultivated tomato plants are extremely susceptible to the two-spotted spider mite Tetranychus urticae Koch. Selection for pest resistance is usually a crucial step required to achieve successful genetic resistance transfer from wild into cultivated tomato genotypes. S. habrochaites LA2329, a wild relative of tomato, is highly resistant to arthropods. Its resistance has been attributed to the presence of a high density of type IV and type VI trichomes and abundant production of 7-epi-zingiberene, a sesquiterpene hydrocarbon. The interspecific backcross hybrids used in this research were derived from the cross between the wild relative tomato, S. habrochaites LA2329, and the cultivated …

Field Evaluation Of Tobacco Engineered For High Leaf-Oil Accumulation, James Perry

Theses and Dissertations--Plant and Soil Sciences

The biofuel market is dominated by ethanol and biodiesel derived from cellulosic and lipid-based biomass crops. This is largely due to the relatively low costs and reliability of production. At present, production of non-food plant-derived oils for biofuel production in the U.S. is minimal. A research team from the Commonwealth Scientific and Industrial Research Organization (CSIRO), an independent Australian federal government research institution, has developed an efficient transgenic system to engineer oil production in tobacco leaves. This novel system is comprised of multiple transgenes that direct the endogenous metabolic flux of oil precursors towards triacylglycerol (TAG) production. Additional genes were …

Impact Of A Warmed Environment, Spike Morphology And Genotype On Fhb Levels In A Soft Red Winter Wheat Mapping Population, Elisane Weber Tessmann

Theses and Dissertations--Plant and Soil Sciences

Fusarium head blight (FHB) is a serious disease of wheat (Triticum aestivum) and other small grains; disease severity is affected by temperature and rainfall. This research comprised three studies: an artificially warmed experiment during 2016-2017, a morphology study and an FHB resistance screening study in 2015-2016, using approximately 250 wheat cultivars and breeding lines from programs in the eastern US. The location was the University of Kentucky Spindletop Research Farm in Lexington, KY. Higher levels of Fusarium damaged kernels and the toxin deoxynivalenol (DON) were observed in the warmed treatment compared to the control, and plant development was …

Salt Stress Induces Non-Cg Methylation In Coding Regions Of Barley Seedlings (Hordeum Vulgare), Moumouni Konate, Michael J. Wilkinson, Benjamin T. Mayne, Stephen M. Pederson, Eileen S. Scott, Bettina Berger, Carlos M. Rodriguez Lopez

Horticulture Faculty Publications

Salinity can negatively impact crop growth and yield. Changes in DNA methylation are known to occur when plants are challenged by stress and have been associated with the regulation of stress-response genes. However, the role of DNA-methylation in moderating gene expression in response to salt stress has been relatively poorly studied among crops such as barley. Here, we assessed the extent of salt-induced alterations of DNA methylation in barley and their putative role in perturbed gene expression. Using Next Generation Sequencing, we screened the leaf and root methylomes of five divergent barley varieties grown under control and three salt concentrations, …

A Shared Cis-Regulatory Module Activates Transcription In The Suspensor Of Plant Embryos, Kelli F. Henry, Anhthu Q. Bui, Tomokazu Kawashima, Robert B. Goldberg

Plant and Soil Sciences Faculty Publications

The mechanisms controlling the transcription of gene sets in specific regions of a plant embryo shortly after fertilization remain unknown. Previously, we showed that G564 mRNA, encoding a protein of unknown function, accumulates to high levels in the giant suspensor of both Scarlet Runner Bean (SRB) and Common Bean embryos, and a cis-regulatory module containing three unique DNA sequences, designated as the 10-bp, Region 2, and Fifth motifs, is required for G564 suspensor-specific transcription [Henry KF, et al. (2015) Plant Mol Biol 88:207–217; Kawashima T, et al. (2009) Proc Natl Acad Sci USA 106:3627–3632]. We tested the hypothesis that …

Gwas For Fusarium Head Blight Related Traits In Winter Wheat (Triticum Aestivum L.) In An Artificially Warmed Treatment, Elisane W. Tessmann, David A. Van Sanford

Plant and Soil Sciences Faculty Publications

Global temperature increases will affect Fusarium head blight (FHB) levels in wheat (Triticum aestivum L.). A pressing question is whether current sources of resistance will be effective in a warmer environment. We evaluated phenotypic response to disease in 238 soft winter wheat breeding lines and cultivars grown in 2015–2016 and 2016–2017 under control and warmed (+3 °C) conditions. Warming was achieved with heating cables buried 3 cm in the rhizosphere. We measured heading date, plant height, yield, FHB rating, Fusarium damaged kernels (FDK), deoxynivalenol (DON), leaf blotch rating, powdery mildew rating and leaf rust rating. There were significant ( …

Optimizing The Use Of A Liquid Handling Robot To Conduct A High Throughput Forward Chemical Genetics Screen Of Arabidopsis Thaliana, B. Kirtley Amos, Victoria G. Pook, Seth Debolt

Horticulture Faculty Publications

Chemical genetics is increasingly being employed to decode traits in plants that may be recalcitrant to traditional genetics due to gene redundancy or lethality. However, the probability of a synthetic small molecule being bioactive is low; therefore, thousands of molecules must be tested in order to find those of interest. Liquid handling robotics systems are designed to handle large numbers of samples, increasing the speed with which a chemical library can be screened in addition to minimizing/standardizing error. To achieve a high-throughput forward chemical genetics screen of a library of 50,000 small molecules on Arabidopsis thaliana (Arabidopsis), protocols using a …

Kelch F-Box Protein Positively Influences Arabidopsis Seed Germination By Targeting Phytochrome-Interacting Factor1, Manoj Majee, Santosh Kumar, Praveen Kumar Kathare, Shuiqin Wu, Derek Gingerich, Nihar R. Nayak, Louai Salaita, Randy Dinkins, Kathleen Martin, Michael M. Goodin, Lynnette M. A. Dirk, Taylor D. Lloyd, Ling Zhu, Joseph Chappell, Arthur G. Hunt, Richard Vierstra, Enamul Huq, A. Bruce Downie

Horticulture Faculty Publications

Seeds employ sensory systems that assess various environmental cues over time to maximize the successful transition from embryo to seedling. Here we show that the Arabidopsis F-BOX protein COLD TEMPERATURE-GERMINATING (CTG)-10, identified by activation tagging, is a positive regulator of this process. When overexpressed (OE), CTG10 hastens aspects of seed germination. CTG10 is expressed predominantly in the hypocotyl, and the protein is localized to the nucleus. CTG10 interacts with PHYTOCHROME-INTERACTING FACTOR 1 (PIF1) and helps regulate its abundance in planta. CTG10-OE accelerates the loss of PIF1 in light, increasing germination efficiency, while PIF1-OE lines fail to complete germination in …

First Interspecific Genetic Linkage Map For Castanea Sativa X Castanea Crenata Revealed Qtls For Resistance To Phytophthora Cinnamomi, Carmen Santos, Charles Dana Nelson, Tetyana Zhebentyayeva, Helena Machado, José Gomes-Laranjo, Rita Lourenço Costa

Forest Health Research and Education Center Faculty Publications

The Japanese chestnut (Castanea crenata) carries resistance to Phytophthora cinnamomi, the destructive and widespread oomycete causing ink disease. The European chestnut (Castanea sativa), carrying little to no disease resistance, is currently threatened by the presence of the oomycete pathogen in forests, orchards and nurseries. Determining the genetic basis of P. cinnamomi resistance, for further selection of molecular markers and candidate genes, is a prominent issue for implementation of marker assisted selection in the breeding programs for resistance. In this study, the first interspecific genetic linkage map of C. sativa x C. crenata …

The Soybean Rfg1 Gene Restricts Nodulation By Sinorhizobium Fredii Usda193, Yinglun Fan, Jinge Liu, Shanhua Lyu, Qi Wang, Shengming Yang, Hongyan Zhu

Plant and Soil Sciences Faculty Publications

Sinorhizobium fredii is a fast-growing rhizobial species that can establish a nitrogen-fixing symbiosis with a wide range of legume species including soybeans (Glycine max). In soybeans, this interaction shows a high level of specificity such that particular S. fredii strains nodulate only a limited set of plant genotypes. Here we report the identification of a dominant gene in soybeans that restricts nodulation with S. fredii USDA193. Genetic mapping in an F2 population revealed co-segregation of the underlying locus with the previously cloned Rfg1 gene. The Rfg1 allele encodes a member of the Toll-interleukin receptor/nucleotide-binding site/leucine-rich repeat class of …

Reciprocal Effect Of Parental Lines On The Physiological Potential And Seed Composition Of Corn Hybrid Seeds, Juliana F. Santos, Lynnette M. A. Dirk, A. Bruce Downie, Mauricio F. G. Sanches, Roberval D. Vieira

Horticulture Faculty Publications

Obtaining corn hybrid seeds (Zea mays L.) with high vigour depends on the parental lines and the direction of the cross, and this relates to seed desiccation tolerance and composition. This research studied reciprocal crosses between pairs of proprietary, elite parent lines (L1 and L5; L2 and L4) producing hybrid seeds with different qualities attempting to correlate vigour with seed composition, focusing on storage proteins, starch and soluble sugar amounts. Four corn hybrid seed lots produced from reciprocal crosses were compared (HS 15 with HS 51, and HS 24 with HS 42) by assessing germination, vigour, and seedling emergence …

Effects Of Cultivar And Maternal Environment On Seed Quality In Vicia Sativa, Rong Li, Lijun Chen, Yanpei Wu, Rui Zhang, Carol C. Baskin, Jerry M. Baskin, Xiaowen Hu

Biology Faculty Publications

Production of high quality seeds is of fundamental importance for successful crop production. However, knowledge of the effects of increased temperature resulting from global warming on seed quality of alpine species is limited. We investigated the effect of maternal environment on seed quality of three cultivars of the leguminous forage species Vicia sativa, giving particular attention to temperature. Plants of each cultivar were grown at 1700 and 3000 m a.s.l., and mass, germination, electrical conductivity (EC) of leakage and longevity were determined for mature seeds. Seeds of all three cultivars produced at the low elevation had a significantly lower …

Impact Of A High Oil And Protein On Agronomic Traits And Overall Seed Composition In Soybean, Maythem Al-Amery

Theses and Dissertations--Plant and Soil Sciences

New soybean lines have been developed with significantly higher oil, protein + oil and higher meal protein. These soybeans contain a VgD1 gene (highly active acyl-CoA:diacylglycerol acyltransferase, DGAT from Vernonia galamensis (VgDGAT1A) produces much higher oil synthesis and accumulation activity in soybean. Soybean with active DGAT from Vernonia galamensis (VgDGAT1A) has active TAG biosynthesis relative to other DGATs including from soybeans and Arabidopsis. DGATs catalyze the final step of TAG synthesis: DAG (diacylglycerol) + acyl-CoA → TAG + CoASH (Coenzyme A is notable for its role in the synthesis and oxidation of fatty acids, and the oxidation of pyruvate in …

Influence Of Source Credibility On Consumer Acceptance Of Genetically Modified Foods In China, Mingyang Zhang, Chao Chen, Wuyang Hu, Lijun Chen, Jintao Zhan

Agricultural Economics Faculty Publications

This paper examines the reasoning mechanism behind the consumer acceptance of genetically modified foods (GMFs) in China, and investigates influence of source credibility on consumer acceptance of GMFs. Based on the original Persuasion Model—which was developed by Carl Hovland, an American psychologist and pioneer in the study of communication and its effect on attitudes and beliefs—we conducted a survey using multistage sampling from 1167 urban residents, which were proportionally selected from six cities in three economic regions (south, central, and north) in the Jiangsu province through face to face interviews. Mixed-process regression that could correct endogeneity and ordered probit model …

Identifying Rare Fhb-Resistant Segregants In Intransigent Backcross And F2 Winter Wheat Populations, Anthony J. Clark, Daniela Sarti-Dvorjak, Gina Brown-Guedira, Yanhong Dong, Byung-Kee Baik, David A. Van Sanford

Plant and Soil Sciences Faculty Publications

Fusarium head blight (FHB), caused mainly by Fusarium graminearum Schwabe [telomorph: Gibberella zeae Schwein.(Petch)] in the US, is one of the most destructive diseases of wheat (Triticum aestivum L. and T. durum L.). Infected grain is usually contaminated with deoxynivalenol (DON), a serious mycotoxin. The challenge in FHB resistance breeding is combining resistance with superior agronomic and quality characteristics. Exotic QTL are widely used to improve FHB resistance. Success depends on the genetic background into which the QTL are introgressed, whether through backcrossing or forward crossing; QTL expression is impossible to predict. In this study four high-yielding soft red …

Characterizing Genotype X Management Interactions On Soybean Seed Yield, David A. Marburger, Bryson J. Haverkamp, Randall G. Laurenz, John M. Orlowski, Eric W. Wilson, Shaun N. Casteel, Chad D. Lee, Seth L. Naeve, Emerson D. Nafziger, Kraig L. Roozeboom, William J. Ross, Kurt D. Thelen, Shawn P. Conley

Plant and Soil Sciences Faculty Publications

Increased soybean [Glycine max (L.) Merr.] commodity prices in recent years have generated interest in high-input systems to increase yield. The objective of this study was to evaluate the effects of current, high-yielding cultivars under high- and low-input systems on soybean yield and yield components. Research trials were conducted at 19 locations spanning nine states from 2012 to 2014. At each location, six high-yielding cultivars were grown under three input systems: (i) standard practice (SP, current recommended practices), (ii) high-input treatment consisting of a seed treatment fungicide, insecticide, nematistat, inoculant, and lipo-chitooligosaccharide (LCO); soil-applied N fertilizer; foliar LCO, fertilizer, …

Field Evaluation Of Burley Lines Containing Alleles Minimizing Nicotine To Nornicotine Conversion, Cameron G. Shelton

Theses and Dissertations--Plant and Soil Sciences

CYP82e4, CYP82e5, and CYP82e10 mutant alleles that minimize the conversion of nicotine to nornicotine have been introgressed into numerous existing low converting (LC) burley varieties and parental lines developed by the Kentucky-Tennessee tobacco breeding program. A backcross breeding protocol was utilized, with the objective being the creation of "e3" varieties that differed from their LC counterparts only for nornicotine and nitroso-nornicotine content. Field studies were conducted in Kentucky and Tennessee during the 2013 growing season, with 17 prospective parental lines and 20 prospective commercial varieties grown and compared to their original counterparts. Most of the e3 lines were not morphologically …

Optimization Of Doubled Haploid Production In Burley Tobacco (Nicotiana Tabacum L.), Ezequiel De Oliveira

Theses and Dissertations--Plant and Soil Sciences

Doubled haploidy (DH) is a plant breeding technique that is often utilized by plant breeders to minimize the time required to reach homozygosity in breeding lines. The first objective of this study was to compare two methods of generating DH lines in tobacco (Nicotiana tabacum L.). Inbred burley tobacco varieties TN 90LC and GR 149LC were used to produce both androgenic derived doubled haploids (ADDH) and maternally derived doubled haploids (MDDH). The relative agronomic performance of TN 90LC and GR 149 LC ADDH and MDDH lines was compared when used either as pure-line cultivars or when used for the …

Genetic And Functional Analysis Of Host Genes Involved In Pathogenic And Symbiotic Legume-Microbe Interactions, Fang Tang

Theses and Dissertations--Plant and Soil Sciences

Legumes form symbiotic and pathogenic interactions with microbes. Understanding the molecular mechanisms underlying the legume-microbe interactions would help us to improve crop production in a sustainable manner. This thesis covers two independent research projects. The first project was to study the role of alternative splicing in RCT1-mediated disease resistance. RCT1 is a TIR-NBS-LRR-type plant resistance (R) gene in Medicago truncatula that confers broad-spectrum resistance to Colletotrichum trifolii, a fungal pathogen that causes anthracnose disease in Medicago. RCT1 undergoes alternative splicing at both coding and 3'-untranslated regions, thereby producing multiple transcript variants in its expression profile. …

Selection And Basis For 2,4-D (2,4-Dicholorphenoxyacetic Acid) Tolerance In Red Clover (Trifolium Pratense), Tara L. B. Lewis

Theses and Dissertations--Plant and Soil Sciences

A red clover (Trifolium pratense) population (UK), from a cross between the cultivar Kenland and a 2,4-D tolerant population (Florida), was recurrently selected for 2,4-D tolerance with evaluations after the 6^th, 7^th, and 8^th selection cycles. All UK populations were more 2,4-D tolerant than Kenland. The 2,4-D tolerance following the 6^th selection cycle was similar to the Florida population and tolerance was increased following 7 and 8 cycles of selection by removing plants showing 2,4-D injury and doubling the rate of 2,4-D used for selection.

Yield and forage quality were evaluated in …